1. Field of the Invention
The present invention relates to a motor vehicle antitheft system of the type comprising an antitheft mechanism comprising a housing in which a member, particularly a key, for manually controlling the starting of the vehicle engine and the locking of the vehicle steering column is inserted and used in order, on the one hand, to unlock, or release, one shaft of the vehicle steering column in terms of rotation and, on the other hand, to control the starting of the engine and, conversely, to stop the engine and lock or immobilize the steering column shaft again.
2. Description of the Related Art
More particularly, the manual control member is mounted so that it can move axially between a pulled back position in which it locks the steering column and a pushed forward position in which it unlocks the steering column.
It is mounted so that it can rotate between at least one angular position of rest and one angular position of use, for example of starting or operating the engine, in which, so as to avoid accidentally immobilizing the steering column during use, particularly when the vehicle is traveling along, it cannot be pulled axially back.
The manual control member is connected in terms of rotation to a rotary output member forming a cam which is capable of collaborating with a control finger carried by a latch bolt to control the movements of the latter which is mounted to slide in the housing between a deployed antitheft position toward which it is elastically urged and in which it projects through an opening of the housing to immobilize in terms of rotation one member of the steering column when the control member is in the angular position of rest and in the pulled back locked position, and a pushed-in position retracted inside the housing.
Finally, it is connected in terms of rotation to a multi-position switch/interrupter assembly for powering various corresponding electrical circuits, of which there are usually four, and which include, in succession, a xe2x80x9cSTOPxe2x80x9d position (corresponding to the extreme angular position of rest of the manual control member), a xe2x80x9c+ACCESSORIESxe2x80x9d position, a xe2x80x9c+CONTACTxe2x80x9d position and a xe2x80x9cSTARTxe2x80x9d position (corresponding to the other opposite extreme angular position).
In a so-called xe2x80x9cmechanicalxe2x80x9d design of such an antitheft system, the manual control member is a key, the shank of which is accommodated axially in the barrel of a lock which, when the key is the right key, allows an output rotor to be turned to control the antitheft latch bolt and the multi-position rotary interrupter.
Successive evolutions in such a type of antitheft system have culminated in particularly reliable and compact designs, it being possible in particular for the entire antitheft mechanism with its lock to be housed as a single unit in a tube adjacent to the steering column of reduced dimensions with, in particular, in the case of the products marketed by the applicant, an inside diameter of the order of about 35 mm.
The general desire among motor manufacturers to standardize components and equipment within a range of vehicles, and for the various versions of the same model, in particular culminates in a standardization of the overall design of the steering column and of its antitheft mechanism, more particularly the design of the electromechanical cam-latch bolt-interrupter assembly which, in addition, has to meet a collection of legal standards which further complicate its design and homologation.
However, it has also been found that it is desirable for certain vehicles to be fitted with more reliable, so-called xe2x80x9csecurexe2x80x9d antitheft systems, while at the same time improving the comfort of use and in particular the ergonomics of manipulation while at the same time meeting the standards, which entails resorting to a manual control member that can move axially and in terms of rotation in order to carry out the aforementioned maneuvering cycles.
In an xe2x80x9celectronicxe2x80x9d antitheft system of this type, the coding of the antitheft system is no longer obtained by the matching of the right key with a barrel-type lock, but is obtained by means of an electronic identification device which in particular comprises an electronic identifier belonging to the authorized user and a unit for identifying an authorized user of the vehicle, fitted onboard the vehicle and which supplies an encoded antitheft signal when the correct identifier is recognized.
The electronic device is of the so-called xe2x80x9chands-freexe2x80x9d type where all of the interrogation and recognition or identification steps are performed without the user having to perform any maneuver or particular action other than those which allow him to enter the vehicle.
It may also be of the type in which the user has possession of an identifier in the form of a badge which he introduces manually into a housing onboard the vehicle.
Designs have thus been proposed in which the manual member for controlling the antitheft mechanism is a control knob replacing the key and which is permanently on the vehicle and in which designs it is associated with a motorized, particularly electromagnetic, member for immobilizing the control knob in terms of rotation, disabling or retraction of which, with a view to releasing the knob, is controlled by an electronic control circuit when an encoded antitheft signal is supplied by the identification unit.
Various examples of such a design are described for example and depicted in document EP-A-0742127. It is noted, however, that these examples do not meet the legislation because the immobilization or release of the steering column shaft are not brought about by an axial movement of the operating knob.
Another example is described and depicted in document WO-A-99/14,085 in which the manual control member is of a design that meets the standards whereby it is necessary for it to be manipulated axially and in terms of rotation in order to release or to immobilize the steering column shaft. It will, however, be noted that the overall ergonomics of the system are not satisfactory as far as the user is concerned because it is impossible for the user to determine whether the inability to rotate the operating knob is the result of defective operation of the identification system and/or of the identification.
In general, the ergonomics are not the same, from the user""s point of view, as those of a xe2x80x9cmechanicalxe2x80x9d antitheft system to which he may have been accustomed, and in which introducing the key into the lock then starting to turn it corresponds to an identification step.
In order to remedy these drawbacks while at the same time offering a great deal of compactness allowing a mechanical system or an electronic system to be adapted easily to one and the same vehicle, the invention proposes a motor vehicle antitheft system of the type comprising an antitheft mechanism comprising a housing in which a member for manually controlling the starting of the vehicle engine and the locking of the vehicle steering column
is mounted so that it can move axially between a pulled back position in which it locks the steering column and a pushed forward position in which it unlocks the steering column,
is mounted so that it can rotate between at least one angular position of rest and one angular position of use (particularly for starting the engine), in which it cannot be pulled axially back,
is connected in terms of rotation to a rotary output member forming a cam which is capable of collaborating with a control finger carried by a latch bolt to control the movements of the latter which is mounted to move with respect to the housing between a deployed antitheft position toward which it is elastically urged and in which it projects through an opening of the housing to immobilize in terms of rotation one member of the steering column when the control member is in the angular position of rest and in the pulled back locked position, and a pushed-in position retracted inside the housing,
and is connected in terms of rotation to a switch/interrupter assembly, which system comprises a unit for identifying an authorized user of the vehicle, which, after an interrogation and identification step, emits an encoded antitheft signal, and wherein the antitheft mechanism comprises:
a motorized, particularly electromagnetic, member for immobilizing the control member in terms of rotation with respect to the housing, the release of which is controlled when an encoded antitheft signal is supplied by the identification unit to an electronic circuit that controls the immobilizing member;
and a switch which triggers an interrogation and identification step, which is carried by the housing and is triggered by the manual control member.
As claimed in other features of the invention:
the manual control member comprises an axially inclined ramp for controlling the triggering switch which acts on an actuating member thereof when the manual control member is pushed in or pulled axially between its two extreme axial positions, namely the pulled back locked position and the pushed forward unlocked position;
means are provided for axially indexing the manual control member in each of its two extreme axial positions;
the triggering switch comprises an actuating member on which the manual control member acts when it is rotated from its extreme angular position of rest to its position of use, or in the opposite direction;
the actuating member is an actuating ball with which the control ramp or a lateral flank of the control member collaborates;
the control ramp is extended axially backward by a cylindrical bearing parallel to the axis and is delimited laterally by said lateral flank;
the control member comprises a rotor which is mounted so that it can rotate with respect to the housing which forms a stator, between two extreme angular positions, one of which corresponds to said angular position of rest and which is immobilized axially with respect to the stator, and a control rod which is mounted so that it can slide axially with respect to the rotor, to which it is connected in terms of rotation, between a pulled back locked position and an extreme forward unlocked position;
said ramp is formed on the control rod;
means are provided for axially indexing the control rod with respect to the rotor in each of its two extreme axial positions;
the control rod has a radial finger for axially holding the control rod in the pushed forward position which, when the rotor leaves its angular position of rest, extends facing a front annular transverse abutment face of the stator to prevent the control rod from retreating axially backward and which, when the rotor is in its angular position of rest, faces a complementary axial groove so as to allow the axial movements of the control rod in both directions between its two extreme axial positions;
the electromagnetic member for immobilizing the control member in terms of rotation collaborates with the rotor to immobilize it in terms of rotation;
the electromagnetic immobilizing member is an electromagnet of axial orientation, the core plunger of which is urged elastically into the deployed position by a return spring so that it is housed in at least one immobilizing notch formed in an element connected in terms of rotation to the control member when the latter is in its angular position of rest, and it can be electromagnetically returned to the pushed-in position so as to release the control member in terms of rotation;
the immobilizing notch is formed in an annular front face of the rotor of the manual control member;
the electromagnetic immobilizing member and the triggering switch belong to a subassembly constituting a disassemblable part of the housing;
the disassemblable part is of annular overall shape and has the manual control member passing axially through its center;
the disassemblable part comprises a printed circuit board in the shape of a flat annulus oriented transversely which carries said switch and the electromagnetic immobilizing member;
the latch bolt is mounted so that it can slide axially parallel to the axial direction of travel of the manual control member;
the latch bolt is mounted so that it can slide in a direction which is generally radial with respect to the axial direction of travel of the manual control member;
the rear axial end of the control rod is connected in terms of axial translation and in terms of rotation to an operating knob by xe2x80x9cfusexe2x80x9d means which break under the action of a torque of determined value.